Sewing machine cabinet

ABSTRACT

A sewing machine cabinet having a tabletop portion and a pivotable displacement mechanism for holding and shifting the sewing machine into a flatbed sewing position, a cylinder bed sewing position, or a storage position. The cabinet mechanism includes at least one gear train drivingly connected to an elevator member that displaces the sewing machine with respect to the tabletop portion into either sewing position. The gear train is preloaded by a first torsion spring to offset the weight of the sewing machine and thereby facilitate displacement of the machine between the flatbed and cylinder bed sewing positions. A second torsion spring offsets the weight of the sewing machine when the cabinet mechanism pivots the sewing machine to a storage position below the tabletop portion.

United States Patent 1191 Fritts Nov. 11, 1975 1 1 SEWING MACHINE CABINET 21 Appl. No.2 508,799

2,210 5/1912 United Kingdom 312/21 295.016 2/1954 Switzerland 312/25 1,328,532 4/1963 France Ill/217.1 1,923,426 ll/197O Germany l12/2l7.l

Primary Examiner-Roy D. Frazier Assistant Eraminer-Thomas J. Holko Attorney, Agent, or FirmEdward L. Bell; Robert E. Smith; Julian Falk [571 ,7 ABSTRACT A sewing machine cabinet having a tabletop portion and a pivotable displacement mechanism for holding and shifting the sewing machine into a flatbed sewing position, a cylinder bed sewing position, or a storage position. The cabinet mechanism includes at least one gear train drivingly connected to an elevator member that displaces the sewing machine with respect to the tabletop portion into either sewing position. The gear train is preloaded by a first torsion spring to offset the weight of the sewing machine and thereby facilitate displacement of the machine between the flatbed and cylinder bed sewing positions. A second torsion spring offsets the weight of the sewing machine when the cabinet mechanism pivots the sewing machine to a storage position :below the tabletop portion.

5 Claims, 10 Drawing Figures 52 US. Cl. 312/30; 112/2171 [51] Int. Cl. A47B 29/00- [58] Field of Search 312/21, 25, 26, 28, 29, 312/30, 312; 112/2171, 258, 260

[56] References Cited UNITED STATES PATENTS 140,929 7/1873 1.6111 112/217.1 x 217,510 7/1879 Butts 312/312 ux 428.382 5/1890 Donn et a1. 312/25 x 508.031 11/1893 Mack 312/25 1.243750 10/1917 Miller 312/312 x 2,398,696 4/1946 Colegrove 312/28 X 2.738.248 3/1956 Berker 312/29 3.765.739 10/1973 Williams 1. 312/30 3,768,883 10/1973 Kauffman 312/312 x 3,774,872 11/1973 Morelli 312/312 x 3,788,716 l/l974 Roberts et a1. 1 312/29 FOREIGN PATENTS OR APPLICATIONS 625,304 6/1949 United Kingdom 112/260 US. Patent Nov. 11,1975 SheetlofS 3,918,780

Sheet 2 0f 5 US. Patent Nov. 11, 1975 9 gum US. Patent N0v.11, 1975 Sheet4of5 3,918,780

US. Patent Nov.1l, 1975 Sheet50f5 3,918,780

SEWING MACHINE CABINET BACKGROUND OF THE INVENTION This invention relates to sewing machine cabinets and more particularly to a cabinet mechanism for holding and shifting the sewing machine with respect to the cabinet into a flatbed sewing position, a cylinder bed sewing position, or a storage position. I

In cabinets employing cabinet mechanisms of the type described the base of the sewing machine, during flatbed sewing, is normally recessed in the cabinetto a level where the sewing machine workplate is substantially continuous with a work surface of the cabinet. For cylinder bed sewing the cabinet mechanism is usually adapted to raise the sewing machine base away from the cabinet so that the cylinder bed is entirely clear of the cabinet work surface. It is also common practice to adapt a cabinet mechanism to shift the sewing machine into a storage space below the cabinet work surface when the sewing machine is not being used.

Cabinets of compact size relative to the size of the sewing machine supported therein are especially convenient for general household use since they permit accommodation of the sewing machine and cabinet in almost any area of a home or apartmenLI-Iowever, most cabinets that are of compact size include mechanisms that require considerable effort by the user to shift the sewing machine from one position to another.

For example one known cabinet mechanism comprises a bar-linkage arrangement that is manually moved to raise or lower the sewing machine with respect to the cabinet. The bar-linkage merely guides the sewing machine into proper position when a lifting or moving force, in opposition to the weight of the sewing machine, is applied to the mechanism by the user. Operation of this cabinet mechanism requires considerable effort by the user and is often a burdensome inconvenience, especially if frequent conversions are made between the flatbed and cylinder bed sewing positions.

To deal with this problem another known sewing machine cabinet includes a mechanism having an auxiliary motor with pulleys for raising and lowering the sewing machine with respect to the cabinet. However since the cabinet houses the auxiliary motor and pulleys in addition to the sewing machine such cabinet is relatively bulky, cumbersome to move, and difficult to accommodate in most homes and apartments. Furthermore the provision of an auxiliary motor unduly adds to the expense of the sewing machine cabinet.

It is thus desirable to provide a compact sewing machine cabinet having a compact mechanism that permits the sewing machine to be easily shifted from one position to another and does not require a strenuous efiort to accomplish this purpose.

Among the several objects of the present invention may be noted the provision of a novelse-wing machine cabinet having a novel mechanism for shifting the sewing machine relative to the cabinet into a flatbed sewing position, a cylinder bed sewing position, or a storage position; a novel sewing machine cabinet mecha nism employing gears for raising and lowering a sewing machine between a flatbed sewing position and a cylinder bed sewing position; a novel sewing machine cabinet mechanism permitting easy shifting of the sewing machine from one position to another without the user having to lift or work against the entire weight of the sewing machine; a novel sewing machine cabinet mechanism having preload means that permit utilization of a force substantially less than the weight of the sewing machine for raising and lowering the sewing machine between its flatbed and cylinder bed sewing positions; a novel sewing machine cabinet mechanism having an elevator member that fonns a continuation of the cabinet work surface when the sewing machine is in its cylinder bed position; and, a novel sewing machine cabinet mechanism that maintains the sewing machine base parallel to the cabinet work surface as the machine is shifted between its flatbed and cylinder bed sewing positions. Other objects and features will be in part apparent and in part pointed out hereinafter.

SUMMARY OF THE INVENTION.

The present invention relates to a novel sewing machine cabinet having a novel mechanism for shifting a sewing machine relative to the cabinet in a flatbed sewing position, a cylinder bed sewing position, or a storage position. The cabinet preferably includes a table top portion having an opening through which the sewing machine is displaced. The cabinet mechanism includes a frame pivoted to the interior portion of the cabinet for movement into and out of substantial alignment with the tabletop opening. A latching device secured to the underside of the tabletop locks the frame in substantial alignment with the tabletop opening when the sewing machine is in a flatbed sewing position or a cylinder bed sewing position. An elevator member comprising a displaceable tray supports the sewing machine on the frame for movement between the flatbed sewing position and cylinder bed sewing position, and occupies the tabletop opening when the sewing machine is in its cylinder bed sewing position.

A first and second gear train respectively mounted on opposite sides of the frame for communication with corresponding opposite sides of the elevator member, drive the elevator member upwardly or downwardly in the frame by means of follower members fixed to preselected gears for engagement with follower slots on opposite sides of the elevator member. Movement of one gear train causes simultaneous movement of the other gear train due to a common gear shaft between one gear in each respective gear train. Gear train movement is controlled by an actuating member such as a lever that pivots to cause rotation of the gears. The gears are preloaded by a torsion spring to offset the weight of the sewing machine and thereby facilitate up and down movement of the machine between its flatbed and cylinder bed sewing positions. A second torsion spring facilitates pivotal movement of the frame and sewing machine between the storage position and the flatbed sewing position.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings;

FIG. 1 is a side view of the sewing machine cabinet of the present invention with the sewing machine in a storage position;

. FIG. 2 is a view similar to FIG. 1 with the sewing machine in a flatbed sewing position and parts of the cabinet mechanism shown in phantom outline;

FIG. 3 is a view similar to FIG. 2 with the sewing machine in a cylinder bed sewing position;

FIG. 4 is a side view'of the cabinet mechanism posi tioned to support a sewing machine (not shown) for flatbed sewing;

FIG. 5 is an opposite side view of the cabinet mechanism positioned to support a sewing machine (not shown) for flatbed sewing;

FIG. 6 is a bottom view of the cabinet mechanism;

FIG. 7 is a view similar to FIG. 4 showing the cabinet mechanism positioned to support a sewing machine (not shown) for cylinder bed sewing;

FIG. 8 is a view similar to FIG. 5 showing the cabinet mechanism positioned to support a sewing machine (not shown) for cylinder bed sewing;

FIG. 9 is a partially exploded perspective view of the cabinet mechanism; and

FIG. 10 is a perspective view of the elevator member of the cabinet mechanism.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DESCRIPTION OF THE INVENTION Referring to the drawings for a detailed description of the present invention a sewing machine cabinet is generally indicated by reference number 10. The cabinet 10 houses a cabinet mechanism 12 for holding and shifting a sewing machine 14 with respect to an opening 16 in a tabletop portion 18 of the cabinet.

Referring particularly to FIGS. 6 and 9 the cabinet mechanism 12 comprises a frame 20 having a base member 22. A pair of right angle members 24 and 26 respectively having side portions 28 and 30 and base portions 32 and 34, are fastened by fasteners 36 to opposite ends of the base member 22. If desired the base member 22 and the right angle members 24 and 26 can be formed in one piece.

The side portion 28 supports a first gear train 38 comprising a drive gear 40, meshing with a pinion 42 keyed, as by a pin 44 and a shoulder screw 46, to the first main gear 48 in mesh with a first intermediate gear 50 which in turn meshes with a second main gear 52. The gears 40, 48, 50, and 52 in the first gear train 38 are arranged on the side portion 28 in any suitable known matter to mesh as described.

A lever arm 54 includes a pivot shaft 56 (FIG. 9) ex tending through a collar 58 on the side portion 28 and into the drive gear 40. A locking pin 60 inserted into the pivot shaft 56 resides in an elongated slot 62 of the drive gear when a C-rin g 64 is clamped to the end of the pivot shaft 56.

The first main gear 48 in the gear train 38 includes an comprising a second intermediate gear 76 keyed to a shaft 78 recessed in the base 22, which shaft 78 is also keyed to the first intermediate gear in the first gear train 38. The second intermediate gear 76 is arranged to mesh with a third main gear 80 positioned directly opposite the first main gear 48, and with a fourth main gear 82 positioned directly opposite the second main 4 1 gear 52. The gears 76, 80, and 82 in the second gear train 74 are arranged on the side portion 30 in any suitable known manner to mesh as described.

The third main gear includes an eccentric follower pin 84 extending across the side portion 30, which side. portion 30 is also formed with a curved nose portion 86 similar tothe nose portion 68. Likewise the fourth main gear 82 includes an eccentric follower pin 88 extending across a curved C-shaped cutout 90 in the side portion j 30, similar to the cutout 72 in the side portion 28.

Referring to FIG. 9 an elongated rod member 92 disposed adjacent an edge 94 of the frame base 22 is supported at opposite ends by the side portions 28 and 30 of the right angle members 24 and 26. A hexagonal member 97 is pinned to the rod member 92 beyond the side portion 30. A torsion spring 96 disposed on the rod 92 is connected at one end to a ratchet member 98 Q q which is pinned to the rod member 92. The ratchet member 98 engages a pawl member 100 rotatably mounted on the rod member 92. The pawl member 100 I includes a bearing arm 101 arranged to bear against the I base member 22. Abiasing spring 103 is disposed on I the rod 92 intermediate the pawl member 100 and, the side portion 30. The hexagonal member 97 is cranked in a counterclockwise direction by any suitable wrench (notshown) to twist the spring 96 and turn the ratchet 1 member 98 relative tothe pawl member 100, thereby setting the torsion of the spring 96. The pawl member 100, which can rotate on the rod 92 or slide against the biasing spring 103 during the torsion adjustment of the spring 96 can be anchored to the frame base 22 after the torsion adjustment is completed by means of a fastener 105 extending through the bearing arm 101 into the frame base 22. The opposite end of the torsion spring 96 is connected to a torsion transfer member 102 rotatably mounted on the rod 92. The torsion transfer member 102 includes an ear portion 104 straddling the second main gear 52 for connection with one end of a link 106. The opposite end of the link 106 is eccentrically connected to the second main gear" 52.

Under this arrangement the torsion spring 96 tends .to rotate the torsion transfer member 102 in a clockwise direction about the rod 92, with reference to FIG. 9,

thus causing thesecond main gear 52 to rotate in a' The flange 112 includes front and rear elongated slots and 122 that are substantially parallel to the tray portion 118. The slots 120 and 122 accommodate the pins 66 and 70 respectively of the first and second main gears 48 and 52. A U-shaped recess 124 is formed in the flange 112 intermediate the front and rear slots 120 and 122. A guide pin 126 disposed on the flange 112 intermediate the front slot 120 and the U-shaped recess 124 extends through an elongated guide slot 128 formed in the side portion 28.

The flange 114, which is symmetrical to the flange 112, includes front and rear elongated slots 130 and.

132, a U-shaped recess 134, and a guide pin 136 "extending through an elongated guide slot 138 in the side portion 30, corresponding to the slots 120, 122, the recess 124, and the guide pin 126 of the flange 1 12. Similarly the slots 130 and 132 accommodate the pins 84 and 88 respectively of the third and fourth main gears 80 and 82. The base of the sewing machine 14 is immovably secured to the tray portion 1 18 of the elevator member 110 in any suitable known manner.

With reference to FIG. 9 the cabinet mechanism 12 further includes an elongated pivot rod 140 spaced from the rod member 92 and having opposite ends supported in the side portions 28 and 30. A hexagonal member 141 identical to the hexagonal member 97 is pinned to the pivot rod 140 beyond the side portion 30. Identical first and second spaced pivot brackets 142 and 144 are rotatably mounted on the pivot rod 140 adjacent to the side portions 28 and 30 respectively for attachment to the underside of the tabletop 18 by fasteners 148 (FIG. 8). A torsion spring 150 disposed on the pivot rod 140 is connected at one end to a ratchet member 152 that is pinned to the pivot rod 140. The ratchet member 152 is engageable with a pawl member 154 rotatably mounted on the pivot rod 140. The pawl member 154 includes a nearing arm 155 arranged to bear against the underside of the tabletop 18. A biasing spring 156 is diposed intermediate the crank member 154 and the pivot bracket 144. The hexagonal member 141 is cranked in a counterclockwise direction to preset the torsion of the spring 150 in a manner similar to that described for the torsional adjustment of the spring 96. The opposite end of the torsion spring 150 is connected to a torsion transfer member 158 that is rotatably mounted on the pivot rod 140. The torsion transfer member 158 includes a depending flange 160 engageable with the edge portion 94 of the frame base 22. Under this arrangement the torsion spring 150 tends to rotate the torsion transfer member 158 in a clockwise direction (with reference to FIG. 9) about the pivot rod 140 to cause the frame to rotate in a clockwise direction about the pivot rod 140.

Referring particularly to FIGS. 6 and 9 the cabinet mechanism 12 also'includes an elongated latch rod 162 mounted to the underside of the frame base 22, by collar members 164, 166 and 168. A pair of stop pins 170 and 172 extend from the latch rod 162 adjacent to the collar members 164 and 168 to prevent lateral shifting of the rod 162 in the collar members 164, 166 and 168. The latch rod 162 also includes offset end portions 174 and 176, and an intermediate crank portion 178 formed between the collar members 166 and 168. A biasing spring 180 has one end secured to an attachment flange 182 on the latch rod 162, and an opposite end secured to the frame base 22.

A pair of catch members 184 and 186 are fastened to the underside of the tabletop portion 18. The catch member 184 includes a hooked end portion 188 formed to engage the offset end portion 174. The catch member 186, which is symmetrical to the catch member 184, similarly includes a hooked end portion 190. A latch release member 192 comprising a handle portion 194, a U-shaped pivot portion 196, and a rod release flange 198 is pivotally secured on a pivot screw 200 that extends through the pivot portion 196 for af- When the sewing machine 14 is in a storage position in the cabinet 10 (FIG. 1) the frame 20 of the cabinet mechanism 12 is suspended from the pivot rod 140 below the tabletop 18 and is substantially out of alignment with the tabletop opening 16. The weight of the sewing machine 14 thus opposes its upward movement about the rod 140 by the torsion spring 150 (FIG. 9), which furnishes an upward lifting force that is less than the downward weight force of the sewing machine 14.

Upon conventionally pivoting the extension leaf 208 of the cabinet 10 and moving the hinged top portion 210 away from the tabletop opening 16, a slight lifting force can be applied to the sewing machine 14 by the user to supplement the upward force of the torsion spring 150. Thus the machine 14 and the frame 20 are easily pivoted in a counterclockwise direction from the storage position of FIG. 1 to the flatbed sewing position of FIG. 2 wherein the frame 20 of the cabinet mechanism 12 is substantially aligned with the tabletop opening 16. When the frame 20 is thus positioned for flatbed sewing the hooked end portions 188 and 190 of the catch members 184 and 186 engage the offset end portions 174 and 176 of the latch rod 162 to lock the frame 20 in its substantially aligned position with the tabletop opening '16. The hinged top portion 210 is then lowered in'the usual manner to form a continuation of the flatbed portion 212 of the sewing machine 14 as shown in FIG. 2.

To use the sewing machine 14 for cylinder bed sewing the lever arm 54 which extends through the tabletop opening 16 is-pivoted away from the pivot rod 140. With reference to FIGS. 5, 8, 9 and 10, the follower pins 66 and on the main gears 48 and 52 engage the elongated slots 1'20 and 122 on the flanges 112 of the elevator member 1 10 to drive the elevator member 1 10 upwardly from the base 22 of the frame 20 to the cylinder bed sewing position of FIG. 3. The upward movement of the elevator member 110 from the frame base 22 is in a vertical direction dueto the engagement of the guide pin 126 in the guide slot 128. Preferably the guide pin l26'does not interfere with an upper end portion 220 of the guide slot 128.

At the first intermediate gear 50 is joined to the second intermediate gear 76 through the shaft 78 (FIGS. 6 and9) pivotal movement of the lever arm 54 away from the pivot rod 140 also causes simultaneous movement of the second intermediate gear 76 and the third and fourth main gears and 82. The follower pins 84 and 88 on the third and fourth main gears 80 and 82, which engage the elongated slots 130 and 132 on the flange 114, thus drive the elevator member upwardly from the position shown in FIG. 4 to the position shown in FIG. 7. The guide pin 136 on the flange 114 engages the guide slot 138 in the side portion 32 without interfering with an upper end portion 218 of the guide slot 138 and cooperates with the guide pin 126 in the guide slot 128 to ensure vertical movement of the elevator member 110 as it is displaced from the flat bed sewing position (FIGS. 2, 4, and 5) to the cylinder bed sewing position (FIGS. 3, 7 and 8). During such elevation the tray member 118 moves parallel with respect to the tabletop 18 because the pins 66, 70, 84, and 88, which support the tray member 118, lie in a plane parallel to the tabletop 18.

The weight of the sewing machine 14 on the elevator member 1 10 in the flat bed sewing position is opposed by but not overcome by the turning force of the link 106 on the second main gear 52 in response to the torsion of the spring 96. Therefore, the force necessary on the lever arm 54 to pivot it away from the pivot .rod 140 and permit easy raising of the sewing machine 14 from the flat bed sewing position (FIGS. 2, 4 and 5) to the cylinder bed sewing position (FIGS. 3, 7, and 8) is slightly in excess of the difference between the weight of the sewing machine 14 and the opposing force of the torsion spring 96.

With the sewing machine 14 in its cylinder bed sewing position as shown, for example, in FIG. 3 the follower pins 84 and 88 are angularly offset by an angle T from the vertical lines 214 and 216 that pass through the axes of the third and fourth main gears 80 and 82. The follower pin 84 and 88 have thus been rotated over and past the center of the third and fourth main gears 80 and 82 as the cabinet mechanism 12 elevates the sewing machine to its cylinder bed position. The weight of the sewing machine 14 on the elevator member 110 thus exerts a force on the follower pins 84 and 88 that tends to move the elevator member 110 downwardly with reference to FIG. 3. However, this downward movement of the elevator member 110 is limited by engagement of the follower pins 84 and 88 against the end portions 222 and 224 (FIG. 3) of the slots 130 and 132. Consequently the weight of the sewing machine 14 and the torsional force of the 'sping 96 detent the pins 84 and 88 against the end portions 222 and 224 of the slots 130 and 132, thereby detenting the sewing machine 14 in its elevated position for cylinder bed sewing. In a like manner the follower pins 66 and 70 in the slots 120 and 122 of the flange 112 simultaneously rotate over and past the center of the first and second main gears 48 and 52 whereby the follower pins 66 and 70 engage the end portions 226 and 228 (FIG. 8) of the slots 120 and 122, corresponding to the slots 130 and 132.

The end portions 222, 224, 226, and 228 of the slots 130, 132, 120, and 122 are each at predetermined location in the flanges 114, 112 to permit the tray portion 1 18 of the elevator member 1 to align with the tabletop portion 118 when the sewing machine 14 is positioned for cylinder bed sewing (FIG. 3).

Referring particularly to FIG. 3, to reposition the sewing machine 14 from its cylinder bed sewing position to the flatbed sewing position the lever arm 54 is pivoted toward the pivot rod 140. This movement of the lever arm 54 causes the third and fourth main gears 80 and 82 to rotate clockwise by an amount slightly exceeding the angle T to allow the follower pins 84 and 88 to make a reverse pass over the center of the third and fourth main gears 80 and 82. In a like manner the follower pins 66 and 70 (FIG. 8) on the firstand second main gear 48 and 52 simultaneously make a reverse pass over the center of the main gears 48 and 52. Consequently, the weight of the sewing machine 14 on the I elevator member 110, which slightly exceeds. the opposing force of the torsion spring 96, can now cause the main gears 48, 52, 80 and 82 to rotate in a direction that permits downward movement of the elevator member 110 toward the flat bed sewing position. The downward movement of the elevator member 110 is easily controlled by a slight restraining force on the lever handle 54 that is equivalent to the difference between the weight of the sewing machine 14 and the opposing force of the torsion spring 96. As the weight force of the sewing machine 14 exceeds the force of the torsion spring 96 the difference between the two forces detents the sewing machine 14 in its flat bed sewing position.

When the sewing machine 14 is not being used it can be stored from its flat bed sewing position by depress- I ing the latch release member 192 (FIGS. 6 and 9) I which pushes against the offset end portion 176 of the latch rod 162 to pivot the offset end portions 174, and 176 away from the hooked end portions 188 and 190 of the catch members 184 and 186. Upon lifting the hinged top portion 210 the frame 20 is now free to pivot about the pivot rod into a storage position as shown in FIG. 1. It should be noted that the offset end portions 174 and 176 can also be released from the hooked end portions 188 and 190 by manually pushing against the intermediate crank portion 178 of the latch rod 162.

As will be apparent to those skilled in the art, the tray portion ll8 of the elevator member 110 can be pro-v vided with suitable access holes and fastening arrange- I ment (not shown) for anchoring the sewing machine 14 to the tray portion 118, and access holes (not shown) can also be provided in the base member 22 to facilitate access to the tray portion 118. It will also be apparent that the torsional preload force can be applied to any of the main gears in either gear train, and if desired separate preload forces can be applied to more than one main gear.

Some advantages of the novel sewing machine cabinet evident from the foregoing description include a cabinet mechanism that permits easy shifting of the sewing machine from a storageposition to a flatbed sewing position, to a convertible bed sewing position and vice versa, and a portable sewing machine cabinet of compact construction that can be easily accommodated in a home or apartment.

In view of the above it will be seen that the several objects of the invention are achieved and other advantageous results obtained.

As various changes can be made in the above constructions without departing from the scope of the invention it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limand the table surface when the sewing machine is in a second position for. flat bed sewing, a pivotably mounted frame means for supporting the sewing machine in said first and second positions and a third position wherein the sewing machine is disposed for cylinder bed sewing, and a positioning mechanism for holding said frame means and the sewing machine in said first, second and third positions, said positioning mechanism including a preloaded torsion means for assisting elevation of said frame means from said first position.

toward said second position, latch means for releasably locking said frame means in said second position, elevator means on said frame means for supporting and moving the sewing machine between said second and third positions, gear means disposed on said frame means in cooperating relationship with said elevator 9 means for driving said elevator means relative to said frame means between said second and third positions, control means engageable with said gear means for initiating movement of said gear means to drive said elevator means, said preloaded torsion means further including means for assisting said elevator means in moving from said second position to said third position, and locking means for releasably locking said elevator means in said third position.

2. The device of claim 1 wherein said gear means comprise a main gear rotatably mounted on said frame means, torque transmission means being eccentrically connected to said main gear to urge said main gear to rotate in a first direction, follower means comprising an eccentric drive pin on said main gear engageable with said elevator means such that the weight of the sewing machine on said elevator means imposes a weight torque through said drive pin of predetermined value on said main gear in opposition to and exceeding the preload torque on the main gear when the sewing machine is in the second position, whereby the difference between the weight torque and the preload torque detents the elevator means in the second position.

3. The device of claim 2 wherein said elevator means includes a stop surface and said main gear is rotatable in said first direction when said elevator means displaces the sewing machine from the second position to the third position, the eccentric drive pin on said main gear being arranged to move with the main gear over and past the axis of rotation of the main gear to a position wherein said eccentric drive pin engages said stop surfaces when the sewing machine is displaced from the second position to the third operating position, said engagement permitting the weight torque to urge the main gear to rotate in the first direction when the sewing machine is in its third operating position, whereby the sum of the preload and weight torques through said drive pin at said stop surface detent the elevator means in its third position.

4. The device of claim 1 wherein said frame includes a base portion, and said elevator means includes a tray member having two opposite end portions, said gear means comprising a gear train on said frame means at each said opposite end portion of said tray member, said follower means comprising a pair of follower members fixed to each said gear train and engageable with the opposite end portions of said tray member for parallel displacement of said tray member with respect to the table surface during movement of said tray member from one of said positions to the other said position.

5. The device of claim 1 wherein said gear means include a main gear and said elevator means include a follower slot having opposite elongated borders, said follower means comprising a follower member fixed to said main gear and extending into said follower slots such that rotation of said main gear in a first direction causes said follower member to move against one border of said follower slot to move said elevator means 

1. In a sewing machine cabinet for accommodating a sewing machine in a plurality of positions relative to said cabinet and including an interior portion, a table surface having an opening therein for accommodating a sewing machine, cover means for covering the opening when the sewing machine is disposed in a first position for storage beneath said table surface, a pivotable leaf member for cooperating with the sewing machine and the table surface when the sewing machine is in a second position for flat bed sewing, a pivotably mounted frame means for supporting the sewing machine in said first and second positions and a third position wherein the sewing machine is disposed for cylinder bed sewing, and a positioning mechanism for holding said frame means and the sewing machine in said first, second and third positions, said positioning mechanism including a preloaded torsion means for assisting elevation of said frame means from said first position toward said second position, latch means for releasably locking said frame means in said second position, elevator means on said frame means for supporting and moving the sewing machine between said second and third positions, gear means disposed on said frame means in cooperating relationship with said elevator means for driving said elevator means relative to said frame means between said second and third positions, control means engageable with said gear means for initiating movement of said gear means to drive said elevator means, said preloaded torsion means further including means for assisting said elevator means in moving from said second position to said third position, and locking means for releasably locking said elevator means in said third position.
 2. The device of claim 1 wherein said gear means comprise a main gear rotatably mounted on said frame means, torque transmission means being eccentrically connected to said main gear to urge said main gear to rotate in a first direction, follower means comprising an eccentric drive pin on said main gear engageable with said elevator means such that the weight of the sewing machine on said elevator means imposes a weight torque through said drive pin of predetermined value on said main gear in opposition to and exceeding the preload torque on the main gear when the sewing machine is in the second position, whereby the difference between the weight torque and the preload torque detents the elevator means in the second position.
 3. The device of claim 2 wherein said elevator means includes a stop surface and said main gear is rotatable in said first direction when said elevator means displaces the sewing machine from the second position to the third position, the eccentric drive pin on said main gear being arranged to move with the main gear over and past the axis of rotation of the main gear to a position wherein said eccentric drive pin engages said stop surfaces when the sewing machine is displaced from the second position to the third operating position, said engagement permitting the weight torque to urge the main gear to rotate in the first direction when the sewing machine is in its third operating position, whereby the sum of the preload and weight torques through said drive pin at said stop surface detent the elevator means in its third position.
 4. The device of claim 1 wherein said frame includes a base portion, and said elevator means includes a tray member having two opposite end portions, said gear means comprising a gear train on said frame means at each said opposite end portion of said tray member, said follower means comprising a pair of follower members fixed to each said gear train and engageable with the opposite end portions of said tray member for parallel displacement of said tray member with respect to the table surface during movement of said tray member from one of said positions to the other said position.
 5. The device of claim 1 wherein said gear means iNclude a main gear and said elevator means include a follower slot having opposite elongated borders, said follower means comprising a follower member fixed to said main gear and extending into said follower slots such that rotation of said main gear in a first direction causes said follower member to move against one border of said follower slot to move said elevator means toward one of said positions, rotation of said main gear in a second direction causing said follower member to move against the opposite border of said follower slot to move said elevator means toward the another of said positions. 